The present invention generally relates to environmental control systems for vehicles such as aircraft.
A bleed-air driven environmental control system (ECS) may be employed in an aircraft to provide cabin air at a desired temperature and humidity level. Such a system may utilize a bleed-air supplied compressor driven by one or more expansion turbines to produce conditioned air. A typical ECS may be constructed to produce conditioned air at a desired rate irrespective of whether the aircraft may be at ground level or in flight. In many instances, an aircraft at ground level may be in a high-temperature environment. To account for such possibilities, a typical ECS may be constructed to accommodate such high-temperature environment conditions (i.e., worst case conditions). A typical ECS may be constructed to consume bleed air at about a ground level rate even when the aircraft may be in flight at a high altitude.
As can be seen, there is a need for an ECS that may produce conditioned air at a desired rate during sea level and altitude conditions with lower bleed consumption than current systems thus reducing engine fuel consumption and increasing aircraft flight range.